i found this full description on IMDb. it tells who the celebs are that felix meets.

The owner of the shoe store, after Felix makes a deal with him to help him avoid bankruptcy and does so, PAYS Felix the $500 just as he promised he would. Then, when Felix takes the money home so he and his preacher-type owner can go to Hollywood, it is his master who STIFFS him out of the money. But, the ever-resourceful Felix makes it to Hollwood anyway. Once there, he decides to see if he can get employment at Static Studios. For whatever inside joke reason Otto Messmer may have had, Felix has to audition for big-ears and bad-teeth Will Hays (caricature) in order to get a movie job. Hays was a former-USA Attorney General who, following the "Fatty" Arbuckel scandals and trials, was now in charge of seeing that no one in Hollywood got their morals corrupted...or, at least, ensuring the newspapers would not get wind of it. While there, Felix runs into caricatures of Ben Turpin and Charlie Chaplin and decides there is too much competition at Static Studio for him. Outside, Felix hears (and the audience reads) a cry for H-e-l-p! Down in the valley none other than dashing Douglas Fairbanks is tied to a stake and about to be stabbed/stung to death by three hornets (or maybe bumble-bees) and Felix heads to his rescue. But, first, Felix steals a pistol from Willilam S. Hart and flies to Doug's rescue. It turns out that it was only a movie scene being shot but, Cecil B. De Mille, the director is vastly impressed with Felix's work and tells him---in silent-cartoon speech balloon fashion---"Great Stuff" and, while shaking Felix's hand adds: "I'll give you one of those long-term contracts!" Unlike Hitchcock, Cecil didn't appear in front of the camera with out having a dialogue line or two, even if was in a speech-box. He was holding his megaphone in the event Sound came along before this cartoon was released.

This is one very funny cartoon.

Fun movie here that features Felix helping a guy (we're not sure who he is) make enough money (via a gum shoe gag) and travel to Hollywood. There he bothers all sorts of stars, including, yes Chaplin, Ben Turpin and MAYBE DW Griffith? Who knows! I not qualified!